1. Field of the Invention
The present invention generally relates to light-emitting diode (LED) packaging. More specifically, the invention relates to high output ceramic mounted light-emitting diode (LED) packages for motor vehicle headlamp or other applications.
2. Description of Related Art
An LED is one type of semiconductor that generates light when voltage is applied to it. There are various advantages to using LEDs in vehicle headlamp applications, such as long lifetime, low drive voltage, high vibration resistance, and high tolerance of repeated power switching.
However, one problem with LEDs is that they require adequate heat sinking in order to preserve their long life. High output LED packages are subject to failure caused by, among other things, localized hotspots and thermal runaway. A high output LED die is operated with high drive currents resulting in high die or junction temperatures, in the range of 150 degrees Celsius or higher. When the substrate material reaches a high enough temperature, it expands and causes mechanical stresses in the bonded contact, weakening it. The reliability of the connections is limited on standard substrates such as FR4 or flexible circuits.
In view of the above, high output ceramic mounted LED packages are designed such as to be non-reflowable and with low coefficients of thermal expansions (CTEs). However, these design parameters make the assembly of the LED packages costly.
Solder interconnects have traditionally been used in LED packages. However, with high die and/or junction temperatures, solder interconnects have proven to be unreliable.
In view of the above, it is apparent that there exists a need for a connector for an LED package that provides reliable mechanical and electrical connections for LED terminals.